<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>select option标签</title>
</head>
<body>
<form action="#" method="get">
    <select>
        <optgroup label="行政单位">
        <option value="教务处">教务处</option>
        <option value="人事处">人事处</option>
        </optgroup>
        <optgroup label="教学单位">
        <option value="数学系">数学系</option>
        <option value="信息学院">信息学院</option>
        </optgroup>
    </select>
</form>
</body>
</html>